1. Field of the Invention
The present disclosure relates to temperature sensors, and more particularly to total air temperature sensors, such as used in aerospace applications.
2. Description of Related Art
Modern jet powered aircraft require very accurate measurement of outside air temperature for inputs to the air data computer, engine thrust management computer, and other airborne systems. For these aircraft types, their associated flight conditions, and the use of total air temperature probes in general, air temperature is better defined by the following four temperatures: (1) Static air temperature (SAT) or (TS), (2) total air temperature (TAT) or (Tt), (3) recovery temperature (Tr), and (4) measured temperature (Tm). Static air temperature (SAT) or (TS) is the temperature of the undisturbed air through which the aircraft is about to fly. Total air temperature (TAT) or (Tt) is the maximum air temperature that can be attained by 100% conversion of the kinetic energy of the flow. The measurement of TAT is derived from the recovery temperature (Tr), which is the adiabatic value of local air temperature on each portion of the aircraft surface due to incomplete recovery of the kinetic energy. Recovery temperature (Tr) is obtained from the measured temperature (Tm), which is the actual temperature as measured, and which can differ from recovery temperature because of heat transfer effects due to imposed environments.
One ongoing challenge for total air temperature sensors is associated with acoustic noise emission. The aeroelastic developed air disturbance has been termed howl, squeal, roar, and whistle and has been reported to reach a sound pressure level of 82 dBA within the cockpit from fuselage probes. In fluid flows developing a Reynolds number above approximately 50, Kármán vortex streets develop and vortices shed from alternating sides of blunt airfoil trailing edges or bluff bodies. Kármán vortices develop cyclic forces that are mainly perpendicular to the airflow and cause aeroelastic vortex induced vibration. Aeroelastic vortex induced vibration sound generation can effect TAT sensors or any airfoil. Vortex induced vibration may also cause structural failure.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for systems and methods that allow for improved total air temperature sensor performance, including reduced acoustic emissions. The present disclosure provides a solution for these problems.